<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .box {
            /*定义使用flex布局*/
            display: flex;
            /*垂直布局*/
            flex-direction: column;
            height: 100vh;
            width: 100vw;
            background-color: #999999;
        }
        .box1 {
            display: flex;
            flex-direction: row;
        }
        .box1 div {
            flex: 1;
            height: 50px;
        }
        .box1 div:nth-child(1) {
            background-color: yellow;
        }
        .box1 div:nth-child(2) {
            background-color: pink;
        }

        .box2 {
            display: flex;
            flex-direction: row;
        }
        .box2 div{
            flex: 1;
            height: 50px;
        }
        .box2 div:nth-child(1) {
            background-color: coral;
        }
        .box2 div:nth-child(2) {
            background-color: lightgreen;
        }
        .box2 div:nth-child(3) {
            background-color: lightblue;
        }
        .box3 {
            display: flex;
            flex-direction: row;
        }
        .box3 div{
            flex: 1;
            height: 50px;
        }
        .box3 div:nth-child(1) {
            background-color: lightcoral;
        }
        .box3 div:nth-child(2) {
            background-color: lightskyblue;
        }
        .box3 div:nth-child(3) {
            background-color: lightyellow;
        }
        .box3 div:nth-child(4) {
            background-color: lightcoral
        }
    </style>
</head>
<body>
<div class="box">
    <div class="box1">
        <div>box1-1</div>
        <div>box1-2</div>
    </div>
    <div class="box2">
        <div>box2-1</div>
        <div>box2-2</div>
        <div>box2-3</div>
    </div>
    <div class="box3">
        <div>box3-1</div>
        <div>box3-2</div>
        <div>box3-3</div>
        <div>box3-4</div>
    </div>
</div>
</body>
</html>